Control mechanism



July 6, 1943. A. NEWMAN 2,323,411

CONTROL MECHANISM Filed Jan. 21, 1942 3 Sheets-Sheet l INVENTOR AR THURNEWMAN ATTORNEY- 3 Sheets-Sheet 2 7 J nW.

INVENTOR ARTHUR NEWMAN ATTORNEY July 6, 1943. A. NEWMAN 2,323,411

' CONTROL MECHANISM Filed Jan. 21 1942 3 Sheets-Sheet 5 INVENTOR A THU/QNEWMAN ATTORN EY Patented July 6, i943 CONTROL MECHANISM I ArthurNewman, New York, N. Y.

' Application January 21, 1942', Serial No. 427,531

8 Claims.

This invention relates to a control mechanism, particularly although notexclusively adapted for use in. conjunction .with systems for theheating of buildings.

In steam heating systems it is generally re- 7 the specific localityinwhich it is situated. If

no control mechanism whatsoever is employed, the pressure will be builtup to the required level,-

and maintained there while the furnace is in operation regardless ofoutside temperature COR",

ventional controls for this purpose generally employ a pressure switch,frequently of the rockable v mercury type, whereby under certainconditions the switch is actuated to alternately shut oil or turn on thesupply of fuel to the furnace. Such a type of switch is usually employedinconjunction with oil burner installations. When the steam pressureexceeds a certain level, in. accord-.

ance with a setting for predetermined temperatures, the switch willautomatically open the 011'- cuit through the burner motor, and therebyshut off the burner, whereupon the pressure will decrease to ultimatelyproduce a lowering of the temperature within the building. It is obviousthat this type of. control doesnot fully take into considerationtemperature differences between the inside and the outside of thebuildin not the rate of heat loss from the building, which isproportionate to the temperature difference.

The aforesaid failure to. take into considerasuflicient pressure toproduce the required temperature conditions at the locale of thethermostat. The bumer may continue operating continuously, even thoughthe insulating properties of the building may be sufficient to keep thebuilding warm for certain periods of time even with the burner ofl.

It is primarily within the contemplation of my invention to eliminatethe aforesaid shortcomings in the operation of control systems forheating plants. I accomplish my objective, in one form of my invention,by providing a method of permitting the pressure in a steam boiler toattain a certain predetermined value, thereafter maintaining thepressure at substantially that level by an intermittent operation of theburner, depending upon outside temperature conditions. Morespecifically, my system permits burner off" periods of variable durationdepending upon the temperature prevailing goutside the building. Inother words, for low outside temperatures (when there is a comparativelygreat difierence in temperature between the inside and outside of thebuilding), oif periods are relatively short, the on periods in a giventime being relatively frethan if the loss were greater; and under suchconditions the steam pressure will not drop as rapidly, so that therewill be no need of having the burner turned on as frequently as would bethe case under lower outside temperature condition the rate of heat lossis characteristic of the conventional thermostat control systemwhichautomatically shuts off the burner when the tem-. perature in aparticular room and at the point thereof wherethe device is situatedexceeds a predetermined level. When this level is reached and the burnerdiscontinuedjthe building will begin to cool, the rate of heat lossbeing dependent upon the difference between inside and outside teratures. If the heat loss proceeds at a rapid ate because of low outsidetemperature conditions, it might take a considerable time to reheat thehouse. And when the burner is set I into operation by this form'ofcontrol, it is continuously kept in operationso as to maintain tions.With the system of. my invention, the burner would automatically beoperated at comparatively infrequent intervals under the lastmentionedconditions.

It is hence an important object of my invention, particularly inconnection with the aspect thereof above mentioned, to reduce to aminimum the period of operation of a burner while providing sufficientpressure, and consequently sufllcient heat, for the building,-therebyproviding an eillcient and economical heating system. l e

It is another object of my invention to enable an adequate control to'bemaintained under any and all temperature and pressure conditions.

It is within the furthencontemplation of my tion.

invention, in one form thereof, to effectuate vari-' ations in steampressure in accordance with outside temperature conditions.

A further object of this invention is to enable it to be constructed,installed and operated ata minimum of cost and effort.

Other objects, features and advantages will appear from the drawings andthe description hereinafter given.

Referring to the drawings,

Figure 1 is a diagrammatic representation of one form of my invention asapplied to a pressure controlled steam heating system.

Figure 2 is a development obthe drum of Figure 1, showing the slotarrangement therein.

Figure 3 is an end view of the drum and one of the mercury tube switchesassociated there- Figure 5 is a fragmentary perspective of a portion ofthe dial member.

Figure 6 is a vertical section of the thermometer switch employed in myinvention. Figure '1 is a diagrammatic view of a modiflcation ofmyinvention, with a variable pressure arrangement, and

Figure 8 is an elevation of the multiple tube pressure control deviceemployable in one form of my invention.

The drawings illustrate a formof my invention as applied to a steamheating system including a steam boiler I. fired by an oil burneroperated by the motor H in the maincircuit indicated by lines l2 and I3.This circuit contains therein the burner control terminals I4 and IIwhich are adapted to be bridged or electrically connected by the bladeorswitch element 18 carried by the armature i1. This armature iscooperatively associated with the spring l8 and the core l8 of thesolenoid 28, the coil 2| of which is electrically associated withcertain circuits containing circuit-closing and interrupting means to belater described. Sufiice it is at this is in series with the solenoidcoil 2| through the conductors 28 and 24. Under normal conditions, theswitch is inthe open or inoperative condition; but when the pressurewithin boiler H exceeds a predetermined level, the switch 22, by aconventional mechanical mechanism, is rocked into its closed position,to close the circuit through coil 2|, therebyenergizing the solenoid,drawing the armature l1 to the core, and consequently opening the burnercircuit. The par-' ticular construction of the boiler pressure means toactuate mercury switch 22 will not herein he described, inasmuch as itis of a conventional construction well known in the art.

From the above it is thus apparent that the burner firing the boiler canbe turned on and off by the operation of the solenoid 28, and saidsolenoid being operable by the pressure switch 22 and by certain othermeans to be hereinafter set forth.

In accordance with one of the prime objects of my invention, it isdesired to effect an intermittent operation of the burner in accordancewith outside temperature conditions. To accomplish my preferred way ofattaining this objective, I employ as movable means a rotatable drum 2!containing thereon means to actuate certain control switches which inturn are adapted to effect the intermittent actuation of switch elementi8, orany other movable member or control means for starting andstoppingthe fuel supply. Each of said control switches is connected in a circuitincluding the coil 2! of the solenoid 28, and suitable circuit-breakingmeans. In the preferred form of my inventlon. the circult-breaking meansconsist of automatic temperature switches, or switches adapted to beactuated under certain temperature conditions. .It is, however, to beunderstood that in place of such automatic circuit-breaking means,manual means may be employed with equal force and effect.

Specifically, the drum 2! contains a number of slots in the surfacethereof, each of these slots being adapted to receive therein an arm ofa control switch, preferably a rockable mercury switch, for the-purposeof permitting the switch tomove into its closed position when the armdrops into the slot. Althoughslots or openings are illustrated in thedrawing, it is of course understood that elevations or otherswitch-actuating means can be employed with the same effect, within thescope of this invention. In the design illustrated, there are fivegroups of slots arranged" in five rows, 28, 21, 28, 28 and 88, the slotsin each row being movable substantially in a plane perpendicular to theaxis of rotation. Disposed above this cylinder and cooperable with saidrows of slots are the mercury control switches ll, 82, 33, I4 and 88.All the said switches are rockably mounted at 88, in conventionalmanner, and contain the arms 31, 88, I8, 48 and II adapted to beoperatively received by the slots in rows 28, 21, 28, 28 and 28,respectively.

Normally, that is, when the switch arms rest upon the surface of thecylinder, the switches are in their open or inoperative conditions, butwhen the arms are within their corresponding slots, the switches willhave been rocked into their closed positions. It will be furtherobserved that each one of the said switches is independentlyelectrically connected to the coil 2l of the solenoid, the switches II,82, 28, 84 and 88 being parts of circuits containing the lines 42, 48,44, 48 and 48, respectively. If, then, any of the mercury switch arms iswithin one of its coacting slots, the solenoid will beenergized,provided, of course, there is no break in the circuit.

My invention, however, does deliberately provide for breaks in certainof the mercury switch circuits last referred to,--such breaks beingeffectuated by outside thermometer switches 41, 48, 48 and 80. Thesethermometer switches, in the preferred form thereof, consist ofconventional thermometers, each being provided with two electricterminals, one in the vicinity of the base of the mercury column, andthe other at a predetermined point above. For purposes of illustration,thermometer 41 contains base terupper terminal 84 set at 48 Fahr.;thermometer 49 contains base terminal 88 and upper terminal .58 set at33 Fahn; and thermometer 58 contains base terminal 81 and upper terminal88 set at 20? Fahr. The terminals of thermometer appear. V

The aforesaid coupling unit 60 contains a slid- 41 are in series withswitch 3|, the terminals or thermometer 48 are. in series with mercuryswitch 32, the terminals of thermometer are in series with mercuryswitch 33, and the terminals of thermometer 50 are in series with mercury switch 34.

I! the outside temperature is below 56, the

' electrical connection between terminals Ii and 52 or thermometer 41will be broken, but otherwise the mercury column will bridge saidterminals and close the circuit. Similarly, each set of terminals foreach of the thermometers will be opened and closed depending upon thejerential extent of the drum as being 360.

drum, there is-always one switch arm in one of the slots. of these slotswhich is clearly illustrated in the development of the cylindricalsurface of the drum, as shown in Figure 2. It will be observed that inrow 26, there is a single slot 14 at a predetermined location (shownsplit in the development). In the next row 21, the slot 15 is 180removed thereirom,regarding the circumrow 28, there aretwo slots 16 and11 in stagoutside temperature. The manner in which these thermometerswitches serve to control the operation of the oil burner will bedescribed later in this specification..

The drum 2% is mounted on shaft 59 which,

by means of coupling unit II is engageable with shaft 6| upon which isfixed the gear wheel 82.

This gear is operatively connected to the time clock motor 83 throughtheworm .64. The time clock shaft BI is connected to the twenty-fourhour dial 6! through the gears 66 and I1.

This/dial is in continuous operation throughout the twenty-four hours orthe day through the continuous action of motor 63. The dial is providedwith means, to be later described, adapt- I ed during certain periods ofthe day to engage the arm 68hr time-clock mercury switch- 69.. Duringsuch engagement theswitch is elevated whereby it is brought into open orinoperative position. When the ,said mercury switch 69 is in its normalor lowered position, it is in closed condition, thereby closing thecircuit through lines 10 and II, and through .burnerterminals l4 and15', to permit the burner motor II to be actuated when any of the circuts operatively associated therewith are closed. But when the said timeclock switch 68 is in its open position, the circuit through motor H canunder no circumstances be completely closed regardless of the open orclosed positions of th other circuits in the apparatus of my invention.It is.

thus apparent that only when the dial 155 is set ior operation during acertain period of time will the control mechanism be in a, position toserve its intended function. For example, it it is desired to keep thefurnace out of operation during, certain hours of the night, a propersetting of this dial ,will open mercury switch 69' during such time,"and keep the burner motor Ii out of operation, as will more clearlyhereinafter able member 12 associated withshaft 59, sa'd slidable memberbeing connected to armature II. The arrangement is such that when thearmature is attracted to core l9 upon an energizing of the solenoid,member 12 of the coupling will that during one complete revolution ofthe drum.

the-order or entry of the various mercury switch arms into the slots isas follows, the numerals indicating the switch arms in their order ofentry into coacting slots during one complete revolu trated, thearrangement is such that the drum makes one revolution in every-120minutes. The

length of each or the slots is designed to 'be such that it will take'five minutes for each slot to pass a given point during the operativerevolution of thedrum. Hencewith this arrangement, for every completerevolution of the drum, arm

31 of switch 3| Will be Within slot 14 for a total I of five minutes ofrevolution, and will be resting on the surface of the cylinder for atotal of 115 minutes. In other words, mercury switch M will be closedfor the said five minutes and open for the remaining 115 minutes. Hence,if the entire circuit of which mercury switch 3! is a part is closed,the solenoid 20 will be energized by said switch for a maximum totaltime of only five minutes. and de-energized for 115 minutes; and theburner will therefore be on for only five minutes during the two hourperiod,unless low pressure conditions in the boiler will, in cooperationwith pressure switch 22, cause a switching on of the burner, as willmore fully hereinafter appea 4 If mercury switch arms 3! and 38 areconsidered together, there will be, under'slmilar closed circuitconditions, two 5 minute periods 01 operation of the burner duringa'two-hour period.

I It mercury switches 31, 38 and 39 are considered operatively engagemember 13, thereby opera j tively uniting shafts 59 and SI From theabove it is apparent that whenever.

solenoid N is energized, the drum 25 will. be I operatively connected tothe time-clock motor 68 and will be rotated thereby. At the same time,

that is, when the drum is in rotation, the oil burner terminals i4 andIE will be electrically disconnected, so that the burner isat such timein its oil condition. v

The slots in the drum are so arranged, in the preferred form of myinvention illustrated, that an arm of at least one of the mercuryswitches thereabove is at all times disposed within 'a slot.

In other words, regardless of the positionot the together, there will befour 5 minute periods of operation of the burner, or a total of twentyminutes, with 100 minutes'as of! intervals. And

if mercury switch arms 81, IO, 39 and 40 are considered together, therewill be eight five min.- ute periods, and oil. periods aggregatingminutes during one complete revolution of the drum.

It thus appears that'the total number of on and oi! periods canbe'cumulative depending upon the operation of the thermometer switches,

as will hereinafter appear.

It is important to note that the length of the slots in row- Ill, andtheir positioning, is such that they extend over all of! periods withrespect to rows 2., 21, 28 and 29 In other words, at such times when allthe arms 31, II, I! and ll are out of the slots, the mercury switch armll will be in one of the slots of row 30.

This is made possible by the spacing And in the last row' In ordertomore fully understand the operation of this system, let us consider thesituation where the outside temperature is 60 Fahr. This temperature isabove the highest temperature set on thermometer 41, or on any of theother thermometers. Hence, the mercury columns in all of thethermometers will close the circuits across the thermometer terminals.Under such conditions, when arm ll mercury switch Ii enters the slot 14,the mercury switch will drop and the circuit therethrough will close.This will close the circuit through the solenoid, where upon thearmature I'I will be drawn to the right to break the connection betweenburner terminals I4 and i5, thereby stopping the operation of theburner. At the same time, the armature has coupled together the shafts58 and Ii, and

. I1 is still within the slot, the drum will stop thereby set the druminto operation. This entire operation merely indicates that when theoutside temperature is high, the burner will be shut oil.

inasmuch as no heat is required.

Now let us consider a drop in outside temperature to 53 Fahn, asindicated in Figure 1. This will ei'lect an opening or the circuit inthe thermometer 41, whereas the circuits through the other thermometerswill remain closed. When the arm II enters slot ll, there will be noaction whatsoever on the solenoid, for although the mercury switch Iiwas closed, the circuit con-,

the left and the circuit across the burner terminals l4 and "is closed.The burner will then be in operation, thereby building up a steampressure so as to supply heat to the building. It should in the meantimebe observed that the drum II is stationary, in view oi the fact thatwith the armature to the left, shafts I! and Ii are uncoupled. k

The burner will remain on as long as it is necessary to enable thesystem to attain the required pressure. It should be borne in mind thatpressure switch 22 is in its lowered or open position when the pressurewithin the boiler is low. It is only when the pressure is built up tothe required level, according to the setting of the pressure switch 22,that this switch will be operatively actuated and the circuittherethrough closed. When this occurs, the solenoid will becomeenergized, and the armature II will be drawn 'to the right to break theconnection at terminals l4 and i5, and stop the burner. At the same timethe complementary members oi the coupling will become engaged and thedrum I! started into rotation. I! the pressure should thereafter dropdown againbelow the preset figure while switch arm I! is still withinthe slot, the pressure switch will drop to its normal open position and,thereby break the circuit through the solenoid. This will cause thearmature to be carried to the left to again bridge burner terminals IIand II, thereby starting the burner into operation again. The burnercontinues to operate until the pressure is built up to again actuate thepressure switch, energize the solenoid and thereby shut off the burnerand start the drum rotating once again. This operation continues untilthe switch arm I! has become disengaged from the slot, whereupon themercury .switch Ii is elevated and the circuit through the solenoidbroken.

Thus it is, in the case above considered, that only during the time-thatthe switch arm I1 is rotating while the pressure is being built up tothe said predetermined level. In other words, the condition of thecircuit while the mercury switch arm 31 is within the slot is such as togive assurance that the pressure switch will be in its raised or closedposition for at least one continuous ilve minute period, or a number ofshorter periods aggregating a total of flve minutes.

After the completion oi the said five minute period, when switch arm 31leaves the slot ll (with the outside temperature still at 53), the

drum will continue rotating because 01 the fact ,that the circuitthrough the solenoid is closed inasmuch as there is always one switcharm within one oi! the slots. That is, the closed conditions of mercuryswitches II, 32, 33 and 34, together with the action of mercury switcharm 4|, will keep the drum in rotation. The burner will thus be shut oi!for a period of 115 minutes, permitting the pressure to decrease.In'this connection it should be noted that under the said outsidetemperature conditions, the rate of heat loss from the building is notvery great, and the building will thus be maintained in a sumcientlywarm condition by virtue of its insulating properties. However, upon thecompletion of one cycle of rotation of the drum, the burner will againbe set into operation to bring the pressure up to the required level.

If the outside temperature should now drop to 45 Fahn, it is obviousthat a longer period at burner operation will be required. This is ef-Iected by two periods each oi a continuous or interrupted ilve minuteoperating time. At such outside temperature, the circuits throughthermometers l1 and II will both be broken, so that during a singlerotation of the drum. mercury switch arms I! and It will, during theirengagement with their respective slots, cause the pressure to remain atthe predetermined level for "a total of-ten minutes.

Similarly, when the outside temperature/is lowered to say 28 Fahn, thecircuits in thermometers l1, l8 and 48 will be opened to cause a totalof four eil'ective switch arm slot engagements during each revolution ofthe drum-the eilective switch arms being 31, 38 and 39. Likewise, whenthe temperature reaches say 15 Fahn, the circuits through all fourthermometers will be broken, to produc eight eilfective slot engagementsof the our switch arms 31, 38, I8 and II.

From the above it is apparent that a plurality of temperature-responsiveswitches, set for predetermined ranges in accordance with outsidetemperature conditions, will automatically consure.

- tions.

by employing a number of normally closed .cir-.

cuits operatively connected to a single solenoid which in turn iselectrically connected both ;to the burner and to a control directly onthe furnace, such as a pressure switch.

The above-described apparatus is operatively associated with thetwenty-four hour dial 65 arm fixed with respect to the tube. Forexample,

above referred-to, and with a suitable electric circuit, of conventionalnature and design, as will be more specifically set forth.

The dial 65 is provided with a plurality of pins 90 upon which can bemounted lift plates 9I, as indicated in Figures 4 and *5. For example,should it be desired to disconnect the entire apparatus between thehours of 11 P. M. and 7 A. M., a successive series of such plates areplaced upon the pins. When, during the rotation of the dial, thepla'te9I at the 11 P.'M. position engages the arm 68 of the dial. mercuryswitch 89, this switch will be'rocked to break the circuit therethrough.Inasmuch as this switch is in series with the burner terminals I4- and Iand the motor I I, the opening of this circuit will prevent the tubesI02, I03, I04 and I05 are operatively associated with arms I01, I09, I09and H0, respectivelyn Each of the said arms .contains therein a threadedhole I II with which an' adjusting bolt I I2 is in threaded engagement.1 Each of said bolts is in abuttable engagement with the next lower arm.It is thus apparent that when 7 nipulating the-'adjusting bolt H2.

the burner from being set into operation regard less of the condition ofthe other circuits of my system. It is only when the last plate at '7 A.M. leaves the switch arm 68 that the apparatus will be permitted tofunction again in accordance with the condition of the control circuits.The switch arm 68, being out of engagement with the lift plates, willpermitthe mercury switch 69 to drop to'its normal closed position,thereby permitting the circuit through the motor to be closed when allother control circuits are closed.

For best operative results, it is preferred that the clock motor 63 bedirectly connected with the outside line 92 to which the main circuit orprimary 93 of the transformer 94 is electricall con nected. Thesolenoid, the mercury switches 3|,

' 32, 33, 34 and 35, the pressure switch 22 .and the thermometerswitches .41, 40, 49 and 50 are operated by stepped down voltage throughthe control circuit or secondary 95 of the transformer.

The above described form of my invention is adapted for use ith apressure switch, such as the switch 22, set at a fixed and invariablepres- Another form of my invention, however, employs an arrangement forvarying the pressure in accordance with outside temperature condi- Thisis effected in connection with the general system above described, andserves to add to the sensitivity and eifectiveness of my invention, I

By referring to Figures 7 and -8 it will be seen that, instead of afixed pressure mercury switch, I employ the unit 96 containing therein apressure sensitive device such as the expansible mem-.

ber 91 operatively connected to the furnace boiler and to River 98. Athe pressure increases, member 91 will expand upwardly against theaction of spring 99, causing the lever 90 to rise against the action ofspring I00,the amount of rise bein inproportion to the pressure. Afilxedto the free end of the lever is the frame or support IOI upon which aremounted four mercury switches each set at dlflerent inclinations withrespect to the horizontal. In the preferred arrangement, the mercuryswitch tubes are pivotly mounted on the member IOI one above the otherat successively greater inclinations, and are immovably held at suchinclinations by adiustable'means. Mercury switch I02 is first set ataninclination fora predetermined steam pressure, for example one pound;and the other switches I03, I04 and I05 are set, at successively greaterinclinations, for

Each of the mercury-tubes is electrically connected in a circuitcontainingthe secondary 95 of thetransformer 94 and the solenoid20certain of the tubes being also electrically connected to certain ofthe thermometer switches located outside of the building The first ofthe mercury switches I02 is connected through line I I3 to the secondthermometer switch 48; the mercury switch I03 is connected to the thirdthermometer switch 49; the third mercury switch I04 is connected to thefourth thermometer switch 50; and the fourth mercury switch I05 is notconnected with any of the thermometer switches, but is connected throughline II4 directly to the solenoid 20. It will be observed that the firstthermometer switch 41 is not connected with any of the aforesaid mercuryswitches in the manner of the other corresponding switches.

The said thermometer switches 41, 48, 49 and 50 are connected with thesolenoid 20 and the mercury switches operatively associated with thedrum 25in the manner shown in Figure 1, and hence will not be againdescribed.

Let us assume that the temperature settings of the terminals at thethermometer switches are similar to those of Figure 1termi,nal 52 beingset at 56 Fahn, terminal 54 at 48 Fahn, terminal 55 at 33 Fahn, andterminal 50 at 20 Fahr.

If the outside temperature is at 53 .Fahr., the

circuit at thermometer 41 will be broken. When the pressure in theboiler reaches one pound, the movement of lever will cause mercuryswitch I02 to move to its closed position, the other mercury tubes beingstill in their open position as indicated in Figures '7 and 8. Upon aclosing of said mercury switch I02, the circuit through line IIIandthermometer switch 48 will be closed, thereby energizing the solenoidand breaking the circuit at burner terminals I4 and I5. As long as theoutside temperature does not fall. as low as 48 Fahn, the heating systemwill be provided with one pound pressure for a period of at least fiveminutes during a two hour period (or for anyother interval in accordancewiththe design of the drum 25).

its closed position. When this occurs, the circuit will be closedthrough line H5 and mercury switch 49, thereby energizing thso'lenoidanddiscontinuing the burner operation. The action of drum 25 in conjunctionwith the circuits associated therewith will assure a maintenance ofthis" pressure for a predetermined timerin accordance with the'systemabove described. Ifthe temperature then drops to 30 Fahn, mercury switchHM will be actuated to its closed position, to close the circuit throughline H6 and thermometer switch 60, and actuate the solenoid 20 in themanner aforesaid. And the pressur will be maintained at three pounds fora predetermined period in accordance with the design of drum 25. Andwhen the pressure within the boiler should attain four pounds, mercuryswitch I will be actuated to close the circuit through line I I4 and thesolenoid Ill-thereby discontinuing the operation of the burner. Thedesign of the control drum 25 will assure the maintenance of thepressure at four pounds for a predetermined period during a completerevolution of the drum.

It will be observed that the introduction oi unit It in the systemcontaining the thermo-electric outside control switches, the drum 25arrangement and the mercury tubes 3!, 32, 33, SI and 35, has beeneifectuated without in any way affecting or interfering with the controlof the burner according to the structure oi Figure l. The arrangement issuch that not only will outside temperature conditions control thenumber and duration of "on" and 011" periods 0! the burner, but also theamount of pressure supplied to the heating system.

It will be further observed that the unit 98 readily permits oiadjustments for predetermined minimum pressures with either fixed orvariable pressure diiierentials between the successive mercury tubestherein. For example, the inclinations of the tubes may be so set as toproduce equal pressures therebetween, such as one pound. It, then, thefirst tube Hi2 is set, at diiierent times, for difl'erent minimumpressures, no ad- Justments are made on the other tubes if the pressuredifferential is to remain one pound. Only the lowermost bolt IIIabutting arm I08 need be adiustably manipulated, and all the tubes willbe uniformly actuated through equal pressure ranges. But should it bedesired to'alter the pressure diflerential between the tubes, that couldbe readily efiected by individually manipulating any or all of the otheradjusting bolts Hi.

My invention has been herein described in connection with a steamheating system operated by.

a motor driven oil burner, and controlled by pressure-sensitive meanssuch as the pressure switch 22 or the pressure-actuated member .1 inunit 06. It is, however, understood that it can be applied to othercontrol systems other than the types specifically hereinabove described.For example, instead of the pressure-sensitive devices 22 and 91,heat-sensitive control devices may be employed, such as heat control inthe return line of a conventional hot water heating system. And insteador burning oil, other fuels may be employed, such as gas for example.With the use of gas, the switch member it would be replaced by a valvefor starting and stoppi g the fuel supply, or by any other movablemember or control means suitable for the purpose.

It is oi course understood that other additional forms and modificationsoi the apparatus and adaptation of the method constituting thisinvention can be employed beyond and in addition to those hereinbetoredescribed, all within the scope of the appended claims.

What I claim is:

.1. In a control mechanism for intermittently operating a ruel supplydevice in a heating system, a main circuit through which said iuelsupply device is controlled, movable control me for starting andstopping said fuel supply devxe a solenoid operatively connected withsaid control means and adapted when energized to hold said control meansin its inoperative position for stopping the fuel supply device, a'control circuit through which said solenoid is controlled, means fornormally holdingsaid control means in its operative position, aplurality of normally open control switches, a plurality of temperatureresponsive switch members set ior difierent predetermined temperatureseach being electrically connected through said control circuit to acorresponding one of said control switches and the said solenoid, androtatable actuating means for intermittently closing said controlswitches comprising a rotatably mounted member containing groups ofspaced switch-actuating means each group being operatively associatedwith a corresponding one or said control switches, the saidswitch-actuating means being spaced in predetermined staggered relationso as to actuate the coacting switches one at a time and a predeterminednumber of .times during each revolution, whereby the frequency orde-energizing oi the solenoid and the consequent release of the saidmovable control means to start the fuel supply device will depend uponthe number of temperature responsive switch members in circuit-breakingcondition. 4

2. In a control mechanism for intermittently operating a fuel supplydevice in a boiler heating system, a main circuit through which saidfuel supply device is controlled, movable control means for starting andstopping said fuel supply device, a solenoid operatively connected withsaid control means and adapted when energized to hold said control meansin its inoperative position for stopping the fuel supply device, acontrol circuit through which said solenoid is controlled, means fornormally holding said control means in its operative position, aplurality of normally open control switches, a plurality of temperatureresponsive switch members set for different predetermined temperatureseach being electrically connected through said control circuit to acorresponding one oi' said control switches and the said solenoid,rotatable actuating means for intermittently closing said controlswitches comprising a rotatably mounted member containing groups ofspaced switch-actuating means each group being operatively associatedwith a corresponding one of said control switches, the saidswitch-actuating means being spaced in predetermined staggered relationso as to actuate the coacting switches one at a time and a predeterminednumber of times during each revolution, and a. boiler control switchelectrically connected through said control circuit to the solenoid andadapted to break the circuit theremechanical means are controlled, aplurality of normally open control switches, a plurality ofcircuit-breaking members each being electrically connected through saidcontrol circuit to acorresponding one 0! said control switches and saidelectro-mechanical means, means to actuate each 01 said control switchesinto its closed position a predetermined number of times during a givencorresponding circuit-breaking members.

interval, whereby the circuit through any actuated control switch andthe electro-mechanical means will be completed and said'movable controlmeans operatively actuated thereby when the correspondingcircuit-breaking member is in its closed condition, and boiler controlmeans comprising a lever movable under the influence of predeterminedboiler conditions, the extent of movement being proportionate to themagnitude of said boiler conditions, a plurality of mercury l0,

tube switches mounted on said lever at various. predeterminedinclinations whereby each switchwill be actuated to its closed conditionat a predetermined position of the lever, there being one V of saidmercury tube switches to correspond with each of said circuit-breakingmembers, each of said mercury tube switches being electrically connectedthrough said control circuit to said electro-mechanicalmeans and one ofthe non- 4. In a control mechanism for regulating a boiler heatingsystem, a fuel supply device, a

7 main circuit through which saidfuel supply device is controlled,movable control means for starting and stopping said fuel supply device,a solenoid operatively connected with said control means, a controlcircuit through which said solenoid is controlled, said solenoid beingadapted, when energized to hold said control means in its inoperativeposition for stopping'the fuel sup- 4 ply device, means for normallyholding said control means in its operative position, a plurality ofnormally open control switches, a plurality of temperature responsiveswitch members set for different predetermined temperatures each beingelectrically connected through said control circuit to a correspondingone of said control switches and the said solenoid, rotatable actuatingmeans for intermittently closing said control switches comprising arotatably mounted member containing groups of spaced switch-actuatingmeans each group being operatWelyassociated with a correspondingone ofsaid control switches, the said switch-actuating means being spaced inpredetermined staggered relation so as to actuate the coacting' switchesone at a time and a predetermined number of times during eachrevolution, and boiler control means comprising a lever movable underthe influence of predetermined boiler conditions, the extent of movement59 being proportionate to the magnitude of said boiler conditions, aplurality of mercury tube switches mounted on said lever at variouspredetermined inclination whereby each switch will be actuated to itsclosed condition at a predetermined position of the lever, there beingone .01 saidmercury tube switches to correspond with, each of saidtemperature responsive switch members, each of said mercury tubeswitches being electrically connected through said control cir- 60 cultto said solenoid and one of the non-corresponding temperature responsiveswitch members.

5. In a control mechanism for regulating a steam heating system, a fuelsupply device, a

main circuit through which said fuel supply device is controlled,movable control means for starting and stopping s'aid'fuel supplydevice, a

solenoid operatively connected with said control means, a controlcircuit through which said solenoid iscontrolled, said solenoid beingadapted when energized to hold said control meansin its inoperativeposition for stopping the fuel supply .device', means for normallyholding said control means in its operative position, a plurality ofnormally open control switches, a plurality of temperature responsiveswitch members set for different predetermined temperatures each beingelectrically connected through said control circuit to a correspondingonce! said control switches and the said solenoid, rotatable actuatingmeans for intermittently closing said control switches comprising. arotatably mounted member containing groups of spaced switch-actuatingmeans each group being operatively associated with a corresponding oneof said control switches, the said switch-actuating means being spacedin predetermined staggered relation so as to actuate the coactingswitches one at a. time and a predetermined number of times during eachrevolution, and boiler control means comprising a pressure-sensitivemember, a plurality of adjacent mercury tube switches operativelyassociated therewith, said mercury tube switches being set at variouspredetermined inclinations whereby each switch will be actuated to itsclosed condition at a predetermined condition of the pressure-sensitivemember, there being one of said mercury tube switches to cor-' respondwith each of said temperature responsive members, each of said mercurytube switches being electrically connected through said control circuitto said solenoid and one of the noncorresponding, temperature responsiveswitch members.

heating plant, a fuel supply device, a main circuit through which saidfuel supply device is controlled, a movable switch member in series withsaid main circuit, a solenoid, a control circuit f through which saidsolenoid is controlled, an arly connected through said control circuitto acorresponding one of said control switches and said solenoid, arotatably mounted cylindrical drum,

a motor for the drum, clutch means for releasably connecting said drumwith said motor, said armature being connected with theciutch meanswhereby upon an operative actuation of the armature and switch member toopen the said main circuit the clutch means will be actuated to connectthe drum with said motor, groups of switch-actuating means associatedwith the drum, each group being operatively associated with acorresponding one of said control switches, the switch-actuating meansinsaid groups being spaced in predetermined staggered relation so as toactuate the coacting switches one at a time and a predetermined numberof times during each revolution of the drum, whereby the circuit throughany actuated control switch and the solenoid will be completed and saidarmature and associated parts will be accordingly operatively actuatedwhen the corresponding circuitclosing member is in its closed condition,a rotatable time clock dial operatively connected to said motor, switchmeans in series with said main electric circuit, and means associatedwith said dial for actuating said last-mentioned switch means atpredetermined times;

7. In a control mechanism for intermittently actuating a fuelsupply-device, a solenoid, a main circuit through which said fuel supplydevice is connected including a burner control switch, a movablearmature associated with said solenoid for operating said burner controlswitch, a rotatably mounted cylindrical. drum. a

,6. In a control mechanism for regulating a motor !or rotating saiddrum, clutch means for releasably connecting said drum with said motorand operatively connected to said armature whereby upon energization ofsaid solenoid said close at a different temperature and each beingelectrically connected in series with a corresponding one or saidcontrol switches and with said solenoid, whereby said solenoid willnormally be deenergized only during the period of closure of any of saidcontrol switches which are in series with an open temperature responsiveswitch to thereby closethe burner control switch and declutch the drumfrom said motor, and condition responsive means for subsequentlyenergizing said solenoid to reengage said clutch means to causecontinued rotation of said drum.

8. In a control mechanism for intermittently actuating a fuel supplydevice, a solenoid, a main circuit through which said fuel supply deviceis connected including a burner control switch, a movable armatureassociated with said solenoid for operating said burner control switch,a rotatably mounted cylindrical drum, a motor for rotating said drum,clutch means for releasably connecting said drum with said motor asaasuand operatively connected to said armature whereby upon energization atsaid solenoid said armature will open said burner control switch, andactuate said clutch means to connect the drum with said motor, aplurality oi normally open control switches each containing a switcharm, said drum containing on the surface thereof a plurality or groupsof spaced slots each group being operatively associated with acorresponding one of said control switches, the slots in said groupsbeing in predetermined staggered relation so as to receive thecorresponding switch arms one at a time and a correspondin number oftimes during each revolution of the drum and thereby cause thecorresponding control switch to be actuated a predetermined number oftimes during each revolution, the slots in one of said groups being orsuch lengths as to extend circumferentially over those portions of thedrum not containing circumferential projections of the other slotswhereby one of said control switches will be maintained closed at alltimes, a Phlrality of temperature responsive switches each adjusted toclose at a different temperature and each being electrically connectedin series with a corresponding one of said control switches and withsaid solenoid, whereby said solenoid will normally be deenergized onlyduring the period of closure 0! any of said control switches which arein series with an open temperature responsive'switch to thereby closethe burner control switch and declutch the drum from said motor, andcondition responsive means for subsequently energizing said solenoid toreengage said clutch means to cause continued rotation of said drum.

ARTHUR NEWMAN.

